Preparation of perhaloalkyl nitrogen-chlorine compounds

ABSTRACT

N,N-dichloro(chlorodifluoromethyl)amine having the following formula:

United States Patent Young et al.

[ Sept. 5, 1972 [54] PREPARATION OF PERHALOALKYL NlTROGEN-CHLORINE COMPOUNDS [72] Inventors: David E. Young, Denville; Lowell R. Anderson; William B. Fox, both of Morristown, all of NJ.

[73] Assignee: Allied Chemical Corporation,

New York, NY.

[22] Filed: Feb. 9, 1970 [21] Appl. No.: 9,953

52 US. Cl. ..260/583 NH, 252/8.l, 252/77, 252/364,'260/566 D, 424/325 51 1m. (:1 ..C07c 87/02 58 Field 6: Search ..260/583 NH [56] References Cited UNITED STATES PATENTS 3,057,849 10/1962 Tullock ..260/583 NH ux 3,052,723 9/1962 Tullock ..260/583 NH 3,137,728 6/1964 Reid ..260/583 NH x Primary Examiner-Joseph Rebold Assistant Examiner-Richard L. Raymond Attorney-Arthur J. Plantamura and Herbert G. Burkard [57] ABSTRACT N,N-dichloro(chlorodifluoromethyl)amine having the following formula:

CF ClNCl 3 Claims, N0 Drawings PREPARATION OF PERI-IALOALKYL NITROGEN- CHLORINE COMPOUNDS BACKGROUND OF THE INVENTION Certain compounds related to ClCF NCl are known and may be found, for instance, in US. Pat. No. 3,057,849. However, the preparation of this compound is not possible by the method described in this patent nor has it been heretofore described. Additionally, the novel dechlorination product, the imine CF NCl, and the reaction product of this novel dechlorinated imine with tetrafluoroethylene, CF NC F Cl, are made possible by the availability of the above compound.

DESCRIPTION OF THE INVENTION This invention relates to the preparation of the novel compounds N,N-dichloro(chlorodifluoromethyl)ami ne, .CF ClNCl N-chloro(difluoromethylene)imine, CF NCl; and N-[2- chlorotetrafluoroethyl(difluoromethylene)]imine, CE

The novel dichloroamine, above, CF ClNCl may be prepared by either reacting cyanogen chloride with two moles of chlorine monofluoride or by the reaction of cyanogen chloride with two moles of perfluoromethyl hypochlorite, according to the following reactions:

b. CIC 5 N 2 CF OCl- CF ClNCl 2 COF In both of these reactions the starting materials are introduced into a closed system, such as in a stainless steel cylinder capped with a conventional metal needle valve, using standard vacuum techniques as described in the appended examples. The reaction is conducted at room temperature and is usually complete in 24 hours. Although room temperature is preferred because of convenience, the reaction may be conducted satisfactorily at temperatures of from 0 to about 50 C. The dichloroarnine product is fractionated through trops at about -80 C. and -l 96 C., and is retained in the 80 C. trap. The yield of final product using either of the above synthetic methods is usually above 90 percent. Atmospheric, subor super-atmospheric pressures may be successfully employed; however, it is convenient to conduct this reaction under the autogenous pressure generated by the reaction and this is preferred. In order to insure complete reaction, at least the stoichiometric amount or preferably a slight excess of the chlorine monofluoride or the hypochlorite is employed, although large excesses will not deleteriously effect the reaction.

The synthesis of the basic N-chloroperfluoroalkyleneimine, CF; NCl, in yields of greater than 80 percent is made possible by the dechlorination of the above CF ClNCl This dechlorination may be conducted in a closed stainless steel system capped with a conventional needle valve. The CF ClNCl is condensed into the system using standard vacuum techniques and heated at about 100-150 C. for 2-5 hours, to yield CF NC] and C1 The free chlorine may be removed from the imine product, for instance, by shaking with mercury at room temperature. The pure CF NCl is then separated from trace amounts of CF NCl and unreacted CF ClNCl by gas chromatography or other suitable methods. No azo-type compounds of the formula RN NR, or azine-type compounds of the formula R N-N R, were observed in the thermolysis products.

The reaction temperature for this dechlorination is preferred and 150C., and particularly at C., but it may be conducted as low as room temperature (25 C.) and as high as 200 C. At room temperature the reaction would be very slow and at 200 C. the rate of reaction may be increased, but the incidence of side reactions becomes more prevalent. It may be conducted at atmospheric, suband super-atmospheric pressures, but it is preferred to conduct the reaction at the autogenous pressure generated by the reaction.

Both, the new N-chloro-amine and -imine compounds above, are useful as flame retardants, fumigants, polymerization initiators and generally intermediates in the preparation of other halogenated amines and imines.

Furthermore, the above imine, CF NCl, may be reacted with tetrafluoroethylene in substantially stoichiometric quantities, at temperatures between 100-200 C., and preferably at C. in a closed system as described above, for about 2 to 6 hours and preferably about 4 hours, according to the following reaction:

The product, N-[2- chlorotetrafluoroethyl(difluoromethylene)]irnine, is a good solvent for highly fluorinated low molecular weight polymers and is a stable heat transfer liquid. It is preferred to conduct this reaction also under the autogenous pressure generated, although atmospheric, subor superatmospheric pressures will not deleteri ously affect the reaction. In small quantities, the CF NCl acts as an initiator in the polymerization of tetrafluoroethylene.

The following examples are illustrative of specific embodiments of the novel compounds of this invention and the processes by which they are prepared:

EXAMPLE 1 A 30 ml stainless steel cylinder was charged with perfluoromethyl hypochlorite, CF OCl, (10 mmoles) and cyanogen chloride, ClCN, (5 mmoles), using conventional vacuum techniques in a Monel-Nickel system at -196 C. The reaction mixture was then warmed to ambient temperatures (2030 C.) in this system and allowed to stand at this temperature for 3 hours. Impurities were then separated from the product by fractionation between traps set at 80 C. and 1 96 C. The new product, a clear colorless liquid, was retained in the 80 C. fraction. It was identified by its gas density molecular weight, infrared spectrum, and its nmr spectrum, as CF ClNCl The yield of this new product based on the starting cyanogen chloride was 91 percent.-

ELEMENTAL ANALYSIS FOR CF ClNCl %C- Found 7.10 Calcd. 7.06 %F- Found 22.43 Calc'd. 22.33 %Cl- Found 60.60 Calcd. 62.43

EXAMPLE 2 A 30 ml stainless steel cylinder was charged with chlorine monofluoride (2O mmoles) and cyanogen chloride mmoles) and reacted as in Example 1 above, the reaction proceeding as follows:

2 ClF ClCN CF ClNCl The product was recovered in 90 percent yield and characterized as in Example 1.

EXAMPLE 3 A 30 m1 stainless steel cylinder was charged with CF CINCI of Example 2, and the reactor heated at 125l35 C. for 3 hours to dechlorinate the starting material as follows:

The free chlorine was removed from the imine product by shaking with mercury at room temperature. Pure CF NCl was then separated from trace amounts of CF NCl and unreacted CF ClNCl by gas chromotography. The product, a gas which boils at 5 C., was recovered in 81 percent yield and identified and characterized by its infrared, mass, fluorine-l9 nmr spectra, and by elemental analysis.

ELEMENTAL ANALYSIS FOR CF: NCl

Calcd. Calcd.

Examples 4 and 5 below, demonstrate that compounds analogous to the dichloroamine, CF CINCI of this invention cannot be dechlorinated by thermolysis in the same manner as the amine of this invention. In other words, the N-chloroirnine product of Example 3 is a unique product made possible by the dechlorination of CF ClNCl EXAMPLE 4 A sample of C F NCl was heated in a pyrex vessel at 200 C. for 30 hours. The only product recovered in 90 percent yield was C F N NC F There was no imine product such as CF CF NCl isolated as was the case in Example 3 above.

EXAMPLE 5 A sample of CF NCl was treated as in Example 4. The only product recoverable in high yield was CF N NCF No imine product such as CF; NC] was recoverable from this reaction.

EXAMPLE 6 This experiment demonstrates the uniqueness and stability of the imine, CF NCl. A sample of CH NCl, when warmed in a closed system as in Example 4 at 25 C. for 1 hour, produces the trimer (CH NCl) This trimer decomposes at C. The N- chlorodifluoroimine, CF NCI, of this invention, neither polymerized nor decomposed under these or more testing conditions.

EXAMPLE 7 A 30 ml stainless steel cylinder was charged with CF2=NCl (5 mmoles) and tetrafluoroethylene, C F4, (5 mmoles), using conventional vacuum techniques at l96 C. The reaction mixture was then allowed to react at C. for about 4 hours. A product isolated in 75 percent yield, by gas chromotography from the crude mixture was identified by its infrared and mass spectra as N-[2-chlorotetrafluoroethyl(difluorometh ylene)]imine, CF NCF CF Cl. It is a stable liquid at ordinary temperatures.

The foregoing detailed description has been given for cleamess of understanding, although the invention is not limited to the exact details shown and described.

We claim:

1. N,N-dichloro(chlorodifluoromethyl)amine, CF ClNCl 2. The method of preparing CF ClNCl of claim 1, comprising reacting cyanogen chloride with chlorine monofluoride at a temperature of from about 0C. to about 50C.

3. The method of preparing CF ClNCl of claim 1, comprising reacting cyanogen chloride with perfluoromethyl hypochlorite at a temperature of from about 0C. to about 50C. 

2. The method of preparing CF2ClNCl2of claim 1, comprising reacting cyanogen chloride with chlorine monofluoride at a temperature of from about 0*C. to about 50*C.
 3. The method of preparing CF2ClNCl2 of claim 1, comprising reacting cyanogen chloride with perfluoromethyl hypochlorite at a temperature of from about 0*C. to about 50*C. 